1. Field of Invention
This invention relates generally to the dispatching of lots of work in a semiconductor foundry and, more particularly, to a comprehensive, dynamic, and real-time dispatching system for semiconductor testing.
2. Description of Related Art
Generally, test operation is the last stage of semiconductor manufacture with the main objectives of separating out bad dies and packages and feeding back the test results. This checking quickly improves product yield. According to the tested product type, test operation is classified as Chip Probing (CP) and Final Testing (FT). These two kinds of test operation use different auxiliary apparatus, but they both have to use the tester to do the test operation. Tester capacity varies and is expensive and limited, but it is also a main resource in test operation, especially in the test foundry. From the viewpoint of production management, tester capacity usage comprises production time for product that needs to be shipped out to external customers in response to orders, engineering time for engineering products that come from some internal experiment for developing advanced technique or monitor operation for stabilizing wafer yield, and idle time. One way to achieve more production time for doing test operations (which would result in increased throughput of product and reduced cycle time of lots) is to efficiently reduce setup time (a part of idle time) taking into account the weekly Master Production Schedule (MPS) target provided by Production Control (PC).
Lot dispatching in a CP/FT test operation can be complex and needs to consider special dispatching properties such as sequence dependent changeover or setup time, re-entrant product flow, various delivery plan requests based on semiconductor foundry business, exception management, and urgent lots interrupting test system behavior. Intelligently arranging and adjusting the lot dispatch list on every tester for full use of tester capacity, on-time delivery, and maximum throughput all at the same time is very important in the management of testing production.
Currently, a Dynamic Lot Dispatching (DLD) system is operating on a test site using the POSEIDON Manufacturing Execution System (MES). The benefits have been such that it is now desirable to transfer this system to other testing sites. Some of these testing sites use PROMIS instead of POSEIDON. Since a DLD system is very closely connected with the MES, a new version needs to be developed that would integrate with PROMIS constraint system and also take care of some situations that the original design of the DLD system did not consider such as dispatching engineering lots according to engineering lots capacity of Testing, solving dispatching conflict between wafer and package lots, and efficiently reducing tester setup times.
Prior approaches include a method of controlling lot dispatches of tool groups, and a method and system for manufacturing using dynamic dispatching of integrated circuit wafer. Other prior art approaches include a method and apparatus for dispatching lots in a factory, as well as a method of controlling lot dispatches of tool groups, and a method to maximize capacity in integrated circuit fabrication. Additional methods and systems for manufacturing using dynamic dispatching of integrated circuit wafer lots are available as is method and apparatus for dispatching lots in a factory. Also, a method and apparatus for control and evaluation of pending jobs in a factory, along with a method and system for the dynamic dispatching in semiconductor manufacturing plants. Another prior art dynamic dispatching method is rule based using the long-term due date and short-term queue time to improve delivery performance. A dynamic lot dispatching method plus a fuzzy logic method and system for adjustment of priority rating of work in process in a production line is included. Output management of processing in a manufacturing plant is another prior art method, as is method for daily target generation and machine allocation with priority. Also, an overall equipment effectiveness on-line categories system and method, and a dispatch and conveyer control system for production control system of a semiconductor substrate is in the prior art.